2 types of spinal reflexes

monosynaptic reflexes characteristics

1 synapse; sensory neuron synapses directly onto a motor neuron 

example of monosynaptic reflexes and when it occurs 

stretch reflex, occurs constantly to keep i upright position 

steps in stretch reflex

stretch stimulate muscle spindle

axons in dorsal send info to sensory neurons

sensory neuron synapses on motor neuron

axons in ventral root send info out from motor neurons

contraction of muscles

polysynaptic reflexes

2 synapses; sensory neuron synapses onto an interneuron, then a motor neuron

example of polysynaptic reflex

withdrawal reflex

steps of withdrawal reflex 

step on sharp object, receptors detect stimulus 

sensory info travels on sensory neuron to spinal cord 

info synapses onto an interneuron 

info synapses onto motor neuron in spinal cord 

motor info travels to legs 

what happens when motor neuron reaches leg in withdrawal reflex

hurt leg will have flexors contract/extensors relax

opposite leg will have flexors relax/extensors contract (plant foot on ground)

skin receptors

pain, temp, touch, pressure, vibration

muscle receptors 

tension, stretching